侧向风及车间距对货车列队行驶影响分析

发布时间：2018-05-19 12:25

本文选题：车辆列队行驶 + 数值仿真　；参考：《吉林大学》2016年硕士论文

【摘要】：随着我国经济的快速发展,我国公路货运量、公路货物周转量在持续增长,载货汽车的保有量也在不断增加。相关统计数据显示,2015年我国共完成公路货运量354.5亿吨,完成公路货物周转量64705亿吨公里,分别占全国货运量及货物周转量的78.7%和35.8%。2014年底我国公路营运载货汽车数量已经达到1453.36万辆,约占全国机动车保有量的5.5%。如何提高载货汽车的燃油经济性,减少有害物的排放已成为当前研究的重要课题。汽车进行列队行驶,能够有效降低队列中各车的油耗,增加道路的通行能力。相关研究显示,车辆在适当间距内进行列队行驶可以使车队平均节油10%以上,具有较高的经济效益和良好的应用前景。但目前国内外对此的研究多是在不考虑侧向风的理想状态下进行的,这势必会对研究结果的准确性产生一定的影响。为此,本文就车辆进行列队行驶时同时受侧向风及不同车间距共同影响的情况开展了相关研究。侧向风及车间距的变化会对队列中各车气动阻力产生不同的影响,本文采用Solidworks软件,参照沃尔沃某款集装箱货车,按照1:1的比例建立了货车仿真模型。为了仿真实验的顺利进行,这里对模型进行了适当的简化,但保留了后视镜、油箱等对空气阻力影响较大的部件。选用基于格子波尔兹曼方法的新一代CFD技术—XFlow作为数值仿真软件,该软件具有无需网格、高效并行、边界条件处理简单、模拟精确等特点。本文首先对单车模型仅受侧向风影响的情况进行了数值仿真实验,目的是为了研究单车风阻系数受不同角度来流影响时的变化规律,同时为两车和三车列队行驶情况提供对比参照。仿真过程中的来流速度恒为25m/s,来流角度变化范围为0°~45°。针对两车和三车列队行驶模型,本文对队列同时受不同角度来流及车间距共同影响的情况进行了仿真实验,实验中来流速度与单车情况保持一致。两车列队行驶时的车间距变化范围为0~30m,来流角度变化范围为0°~20°。相对两车队列而言,由于三车队列的间距变化方式更加复杂,所以为了探究中车位置的变化对车队平均风阻系数的影响,这里首先在无侧向风影响的条件下,就三车间距变化方式为非等间距变化的情况进行了研究。在此基础上,仅对等间距变化的三车队列受不同角度来流影响的情况进行了仿真分析,其间距变化范围1~28m,来流角度变化范围也为0°~20°。仿真实验完成后,根据仿真结果分别对两车和三车队列的燃油节省率进行了计算。结果显示,两车队列和三车队列的平均节油率分别为8.93%和15.01%,节油效果较为明显。根据仿真结果,从速度场和压力场两方面,对车辆气动阻力的形成机理、各车风阻系数变化规律进行了解释分析,为相关研究奠定了一定的理论基础。
[Abstract]:With the rapid development of China's economy, the volume of road freight and the volume of road cargo turnover are increasing continuously, and the quantity of cargo vehicles is also increasing. Relevant statistics show that in 2015, China completed 35.45 billion tons of road cargo and 6.4705 trillion tons of road cargo. It accounts for 78.7% of the national freight volume and freight turnover, respectively, and 35.8.3.8.The number of road cargo vehicles in China has reached 14.5336 million by the end of 2014, accounting for about 5.5% of the total number of motor vehicles in China. How to improve the fuel economy and reduce the emission of harmful substances has become an important research topic. The vehicle can reduce the fuel consumption and increase the capacity of the road. The related research shows that the vehicle can save more than 10% fuel on average when traveling in line within the proper distance, which has high economic benefit and good application prospect. However, most of the researches at home and abroad are carried out under the ideal condition of not considering the lateral wind, which will inevitably affect the accuracy of the research results. Therefore, this paper studies the influence of lateral wind and different vehicle spacing when vehicles are traveling in procession at the same time. The variation of the lateral wind and the distance between the vehicles will have different effects on the aerodynamic resistance of each vehicle in the queue. In this paper, the simulation model of the freight car is established according to the 1:1 scale by using Solidworks software and referring to a certain type of Volvo container truck. In order to make the simulation experiment go on smoothly, the model is simplified properly, but the rear-view mirror and fuel tank are retained, which have great influence on the air resistance. A new generation of CFD technology, -XFlow, based on lattice Boltzmann method, is chosen as the numerical simulation software. The software has the advantages of no grid, high efficiency and parallelism, simple boundary condition processing, accurate simulation and so on. In this paper, first of all, numerical simulation experiments are carried out to study the variation of the wind resistance coefficient when the wind resistance coefficient is affected by the flow at different angles. At the same time for two cars and three cars to provide a comparative reference to the situation. During the simulation, the velocity of flow is 25 m / s, and the angle range is 0 掳~ 45 掳. Based on the two-vehicle and three-car queue model, the simulation experiment is carried out on the condition that the queue is affected by the flow of different angles and the distance between the vehicles. The speed of the incoming flow is consistent with that of the bicycle in the experiment. The range of the distance between the two vehicles is 0 ~ 30 m, and the angle of flow is 0 掳~ 20 掳. Compared with the two-vehicle queue, because the distance between the three-vehicle queue is more complicated, so in order to explore the effect of the change of the position of the middle vehicle on the average wind resistance coefficient of the motorcade, first of all, under the condition of no lateral wind, In this paper, the change of the distance between three cars is studied. On this basis, the effect of different angle flow on the three-car queue with equal spacing is simulated and analyzed. The range of the interval is 1 ~ 28m, and the angle of the incoming flow is also 0 掳~ 20 掳. After the simulation experiment is completed, the fuel saving rates of two and three cars are calculated according to the simulation results. The results show that the average fuel saving rates of the two and three car queues are 8.93% and 15.01, respectively. According to the simulation results, the formation mechanism of vehicle aerodynamic resistance and the variation law of wind drag coefficient of each vehicle are explained and analyzed from two aspects of velocity field and pressure field, which lays a certain theoretical foundation for the relevant research.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U461.1

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